drm/bridge: panel: Introduce drmm_of_get_bridge

Unlike what can be found for other DRM entities, we don't have a
DRM-managed function equivalent to devm_drm_of_get_bridge().

Let's create it.
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-12-maxime@cerno.tech

drivers/gpu/drm/bridge/panel.c

@@ -459,4 +459,39 @@ struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
 	return bridge;
 }
 EXPORT_SYMBOL(devm_drm_of_get_bridge);
+
+/**
+ * drmm_of_get_bridge - Return next bridge in the chain
+ * @drm: device to tie the bridge lifetime to
+ * @np: device tree node containing encoder output ports
+ * @port: port in the device tree node
+ * @endpoint: endpoint in the device tree node
+ *
+ * Given a DT node's port and endpoint number, finds the connected node
+ * and returns the associated bridge if any, or creates and returns a
+ * drm panel bridge instance if a panel is connected.
+ *
+ * Returns a drmm managed pointer to the bridge if successful, or an error
+ * pointer otherwise.
+ */
+struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
+				      struct device_node *np,
+				      u32 port, u32 endpoint)
+{
+	struct drm_bridge *bridge;
+	struct drm_panel *panel;
+	int ret;
+
+	ret = drm_of_find_panel_or_bridge(np, port, endpoint,
+					  &panel, &bridge);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (panel)
+		bridge = drmm_panel_bridge_add(drm, panel);
+
+	return bridge;
+}
+EXPORT_SYMBOL(drmm_of_get_bridge);
+
 #endif

include/drm/drm_bridge.h

@@ -949,6 +949,8 @@ static inline int drm_panel_bridge_set_orientation(struct drm_connector *connect
 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)
 struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,
 					  u32 port, u32 endpoint);
+struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm, struct device_node *node,
+					  u32 port, u32 endpoint);
 #else
 static inline struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
 							struct device_node *node,